mirror vdev or raidz

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mirror vdev or raidz

Postby carpman » Tue Feb 06, 2018 12:45 pm

Hi, i have a 5 bay external sata drive bay and 5 2gb drives which i wish to setup to use for storing files for streaming over plex and some backups of main drives.

I am thinking of using 4 drives plus one as hot spare. During my research I have read that a raidz will give more total space, but mirrored vdev will give better read performance and better redundancy in case of drive failure!

Which would you recommend in this scenario taking into account upgrading to bigger drives in the future.

Thanks
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Re: mirror vdev or raidz

Postby lundman » Thu Feb 08, 2018 4:17 am

If you absolutely need speed, mirror will be faster, and you lose 50% of the space.

If you want space, use raidz, and you will lose 25%.

Personally I really like raidz, it can sustain 5 1080p steams simultaneously, so I don't need "faster" personally.
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Re: mirror vdev or raidz

Postby carpman » Thu Feb 08, 2018 1:36 pm

Thanks for reply,
Was thinking raidz with compression and hot spare, but keep reading mirror vdev are safer for data!

I am using reliable enterprise level drives.
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Re: mirror vdev or raidz

Postby tangles » Fri Feb 09, 2018 9:32 am

Why "hot" spare? sounds like the pool is local from your description.
Might as well use it if you're going to have it spinning all the time and thus gain the storage.

I keep a cold spare handy for my pool and even then, it sometimes ends up in my MacPro for quick/temporary tasks.
And if your data is that important, you shouldn't be using raidz… ;)
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Re: mirror vdev or raidz

Postby lundman » Fri Feb 09, 2018 11:36 am

Yeah, not sure on hotspare myself, i dont think we have automatic fail over done (its part of zed), and someone suggested instead of hotspare, just add it in and go raidz2 instead. But personally, I have cold spare and replace fast if a disk dies. But yes, weigh all information and pick the best course for your case.
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